My second observation was that if black's king is on g8 instead of f8, then Qe8+ Rxe8 Rxe8#. So white needed to check the king without letting him out in order to mate him. That meant at some point being able to play Nd7+ (Ne6+ wouldn't work - black just plays fxe6 and eventually escapes to h7).

One useful aspect is it teaches you to 'read' chess books without needing a board, screen, or diagram. In OTB tournaments, I sometimes go for a stroll while still analyzing the position in my head.

Being very short-sighted (and not always wearing glasses or contacts) may have helped initially. I got into the habit of memorizing things I couldn't actually see.

Missed a Monday puzzle, ouch. At first I thought of Queen sacs, of course, but Qxf7+ didn't seem to go anywhere ... Saw Qe8+, but not the followup.

Thought of ways to deflect the Rook so Qe8 would be mate, but 23 Nxa6 is not forcing enough and may even lose - it is true that neither Knight may be taken: 23 ... Rxa6?? 24 Qe8#, or 23 ... Qxa6?? 24 Qxf7#, or 23 ... hxg5? 24 Nxc7! threatening mate and also the a8-Rook, Black cannot save both and comes out a piece down - but 23 ... g6! seems to win for Black there as now both White Knights are attacked, none of the sacrifices are on, and there seems to be no good continuation after 24 Nxc7 Rd8!

http://books.google.com/books?id=3N...

Earlier perhaps 8...Bd6 = or 8...Bb7 makes even more sense. Black wastes too much tempo attacking pieces in this game, when instead he should have been developing.

This is an excellent game to analyze. White has a clear advantage after 11. Rc1! and a decisive advantage after 12. d5!!

I spotted this one quite quickly, yet several friends who are undoubtedly better players than me struggled. How come?

My thought process was simply this:

1. The action starts with the Ng5 being threatened by the black h6. If the knight can stay on g5, Black is nearly stalemated with a back rank mate close at hand.

2. The standard response to a stalemated king is to check, check, check until dead. So I really want to be able to play a check. And it will almost certainly have to be a knight check cos no other piece has a sensible check to offer.

3. Ne6+ doesn't promise much, so it has to be Nd7+.

4. But my queen is in the way of Nd7+. Can I move my queen away from d7 with tempo?

5. Qe8+ looks tempting. Then kick the black king away from the defence of e8 with the previously advertised Nd7+.

6. Quick spell check of the variations to confirm an unavoidable back rank mate. QED. Thank you very much.

The odd thing is that we all use slightly different methods to find the solution. Some days one method works faster than another. And on other days the reverse happens.

Without using a chess engine, I don't think white is winning at this point. It seems that black messed around too much without getting castled and instead went after the bishop pair with 11...Nh5?. I wonder why black didn't play the easy 11...Bd6 and castle? Notice that 12.Bxd6? cxd6 adds control to c5 which really makes the a4-knight look questionable. White really wanted control over the c5 square, but after black's 11th move everything changed. 12.d5! is one of those opportunistic moves you have to find the moment your opponent makes a mistake. White says "With your king in the center, let's open things up!". Even after this, black stubbornly takes the bishop anyway and falls right into white's hands. I like the way white prevents castling with 16.Rfd1 Bd6 17.Re1+ Be7 18.Rxe7! and now 18...Kxe7 is forced--otherwise after 18...Qxe7 19.Re1 wins material.

It's a clearance sac starting with: